Sheet metal perforating apparatus



Jan. 6, 1942. G F 'wALEg 2,268,787

SHEET METAL PERFORATING APPARATUS Filed Feb. 1'7, 1941 2 Sheets-Sheet 12 W7 /7 /777/7 fl 2 r 26 28 1 Z; ATTORNEYS Jan. 6, 1942. F WALES2,268,787

SHEET METAL PERFORATING APPARATUS Filed Feb. 17, 1941 2 Sheets-Sheet 256 25 22 I Z? 5 F' .4. Q Z; v 6/ 5 [13% @333; 33;} Z v 55 W Z L 9.5 55%476$ 4 2$ 4 46/ 47WA iZ/ wwyi 1 W %IZEGTOR ATTORNEYS Patented Jan. 6,-1942 2,268,787 1 SHEET METAL PERFORATING APPARATUS George F. Wales,Bufialo, N. Y.

Application February 17, 1941, Serial No. 379,185

6 Claims.

This invention relates to a punching unit for sheet material perforatingapparatus of the character shown in my Letters Patent of the UnitedStates No. 1,955,866 granted April 24, 1934.

In the punching units shown in this prior patent the lower or bit endsof the punch bodies were guided solely-in the lower ends of the guidesleeves and this involved considerable cost when changing from one sizepunch to another, inasmuch as such changes necessitated disassemblingthe punch, its guide -sleeve and stripping elements of the unit,substituting a guide sleeve of the required size to suit the new punchbody and reassembllng-of the same with the stripping elements or havingindividual stripping guide assemblies for each size punch.

One of the objects of this invention is to provide a punch unit of thischaracter in which 'nearly all of the stripping elements can be usedwith all sizes of punches and which requires only the substitution ofone punchfor another and the use of a corresponding guide buttonstripper whenever it is necessary to use a punch of a different size,thereby effecting a considerable cost in equipment.

Another object of this invention is to provide improved means forconnecting the heads-to the bodies of punches and also to improve themeans and method of connecting the lower spring sup porting collars ofthe stripping devices to the guide sleeves of the punches.

In the accompanying drawings:

Fig. 1 is a sectional side elevation of a sheet metal perforatingapparatus embodying one'form of this invention.

Fig. 2 is a top plan view of the same.

Fig. 3 is a fragmentary horizontal section, taken on line 3-3, Fig. 1'.

, Fig. 4 is a vertical section showing the manner of securing the headto the body of the punch in accordance with this invention.

Figs. 5, 6 and 7 are vertical sections showing various stages in the useof the method and apparatus for securing the lower spring supportingcollar of the stripping device to the punch guide sleeve in accordancewith this invention.

Fig. 8 is a fragmentary vertical section showing a slightly differentform of the invention compared with that shown in Fig. 1.

In the following description similar characters of referenceindicatelike parts in the several figures of the drawings.

The punching unit which embodies the present invention may be used inconnection with other parts of a sheet metal perforating apparatus (Cl.164-124) I 'which may vary in their detail construction but,

as shown-in Figs. 1, 2. and 3, these other parts include a holder havinga lower base or shoe l which is provided on its upper side'with a dieseat II and a slug chute l2 leading from the underside of this seat toone side of the base and an upper horn or head l3 which is separatedfrom the base by a gap l4 and provided above the die seat with avertical guide opening ii of cylindrical form. The holder is supportedby a templet plate l6 which rests on the bed 9 of the press and issecured to the underside of the holder by a screw I1 and held againstturning horizontally thereon by a locating screw I 8 arranged on theunderside of the holder and engaging with the opening IS in the templetplate. Above the holder is arranged a vertically movable ram 20 whichmay be raised and lowered by any suitable means. The seat ll receives aperforating die 2|, the upper side of which is preferably'arrangedslightly above the surface of the base of the holder and the same isprovided with the usual die opening 22 which receives the slug removedfrom the sheet material workpiece'23, such as sheet metal, during theoperation of perforating the same and delivers the same to the dischargechute '-I2.

The preferred form of punching unit which cooperates withthe die forperforating the workpiece and strips the latter from the punching unitafter the perforating operation is complete may be variously constructedin accordance with this invention, but as shown in Figs. 1, 2 and 3 thesame is constructed as follows:

The numeral 24 represents the vertical body of the punch, the lower endof which forms a cutting bit 25 which cooperates with the upper edge ofthe punching opening 22 in the die 2| for removing a slug from theworkpiece during the operation of forming a hole in this workpiece. Atits upper end the punch body is provided with a head 26 which, togetherwith the punch body, are adapted to be engaged by the ram 20 and moveddownwardly thereby causing the bit to perforate the workpiece.

. annular grooves or recesses 21, for example, two

grooves as shown in Figs. 1 and 4. The grooved part of this body isarranged .within a central opening 28 inthe punch head and metal'fromthe bore of the opening in the head is displaced in- The union of thepunch body and head in this 5 manner may be effected, as shown in Fig.4, by placing the punch body downwardly in the socket 30 of an uprightholder 3| so that the bit is spaced from the bottom of this socket andthe upper end of the body projects above this holder,

then placing the ring-shaped punch head 29 upon the holder 3| so theopening or bore in the head receives the punch body and the upper sidesof the punch body and head are flush, and then subjecting the metal ofthe head immediately around the bore thereof to a squeezing or swagingoperation of an annular swaging bead 32 arranged on the upper side ofthe holder 3| and engaging the underside of the punch headconcentrically with its axis and an annular swaging 2 bead 33 arrangedon the underside of a former 34 and engaging the upper side of the punchhead concentrically with its axis. Upon moving the holder 3| and former34 toward each other between the bed 35 and the ram 36 of a press, the

lower and upper swaging beads 32, 33 displace a part of the metal of thehead inwardly from the bore of the same into engagement with thegrooves-or recesses 21 of the punch body and thus securely interlock andconnect the same.

wardly during the operation of swaging the beads 40 29 from the headinto the grooves 21 of the body. If desired the position of the holder3|, forming die 34, punch body 24 and punch head 26 may be reversedbetween the bed and ram 36 particularly when the punch body fits looselyin the a holder and punch head.

The numeral 31 represents a guide sleeve which is arranged centrallywithin the guide opening i5 of the punch mechanism holder and in whichthe body of the punch slides vertically. The

upper part of the guide sleeve is arranged within an upper collar orguide ring 38 which slides vertically within the upper part of theholder guide opening IS. The upper end of the upper collar engages withthe underside of the punch head 26 55 and its lower end is free to slidedownwardly on the guide sleeve an undetermined extent but the extent ofupward movement of the upper collar relative to the guide sleeve islimited by a downwardly facing annular stop shoulder 39 formed 0 on theupper part of the periphery of the guide sleeve and an upward facingannular shoulder 40 arranged internally on the lower part of the uppercollar and engaging the shoulder 39 of the guide sleeve. 05

The numeral 4| represents a collar secured to the periphery of the guidesleeve at the lower end thereof. Between the upper and lower collars 38and 4| a stripper spring 42 of helical form surrounds the guide sleeveand bears at 70 its upper and lower ends against the upper and lowercollars, respectively, and is preferably under an initial tension whenthe upper and lower collars are spaced apart their fullest extent.

Various means may be employed for connect- 75 When the punch body fits35 ing the lower collar with the guide sleeve but those shown in thedrawings are adapted to produce a permanent connection between the guidesleeve and the lower collar and for this purpose the lower collar andthe guide sleeve are connected in the following manner:

Initially the guide sleeve is provided on the lower part of itsperiphery with a downwardly facing annular shoulder 43 and within thelower part of its bore with an annular temporary rib or bead 44, asshown in Fig. 5. The bore of the lower collar has its lower partenlarged so as to form a downwardly facing annular shoulder 45 withinthis collar. The guide sleeve, upper and lower collars and the springtogether form elements of the means whereby the 'sheet of metal and thepunch are separated or stripped from one another after the operation ofa hole in the sheet of metal has been completed. Preparatory topermanently assembling these stripping elements the same are firststacked loosely in a vertical column by placing the lower collar on asupport block or anvil 46 which rests on the bed 41 .of a press andprovided with a vertical opening 48 in line with the bore of the lowercollar, as shown in Fig. 5, then placing the spring while in a whollyexpanded or relaxed'condition with its lower end in engagement with thetop of the lower collar, then placing the upper collar withits undersidein engagement with the upper end of the spring, and then inserting theguide sleeve downwardly through the upper collar and the spring untilthe shoulder 39 of the guide sleeve engages with the shoulder 40 of thecollar, at which time the lower end of the guide sleeve projects partwayinto the upper small part of'the bore of the lower collar and the lowerexternal shoulder 43 is spaced upwardly from the upper side of the lowercollar, as shown in Fig. 5. After the stripper elements have been thusloosely stacked they are subjected to a further operation for completingthe assembling of the same suitable for use in connection with the punchand die of the sheet metal perforating apparatus. For such completion ofthe stripper unit a swaging or expanding wedge or tool is employed whichhas a large round upper part 49 of a diameter corresponding to the boreof the upper part of the guide sleeve, a lower round part 59 of adiameter equal to the bore of the rib or bead 44 and the reduced lowerpart 5| of the opening in the supporting block 41, and a centraldownwardly tapering conical part 52 arranged between the large upperpart 49 and the'small lower part 50 of the swaging tool. This tool ispassed with its reduced part lowermost through the stack of looselyassembled stripper elements until its lower small end engages the smallpart 5| of the guide opening in' the supporting block and the largeupper part of the tool engages with the bore of the guide sleeve and thesmall lower end of the conical part 52 of the tool reaches the bore ofthe temporary bead 44 in the guide sleeve. Upon now moving the swagingor expanding tool downwardly another step by means of the ram 53 of apress, or otherwise, while the supporting block 46 rests on the bed ortable 41 of a press, the tapering part of this tool, by engaging withthe internal bead or rib 44 of the guide sleeve, will move the latterdownwardly until the shoulder 43 of the sleeve engages the upper side ofthe lower collar 4|, as shown in Fig. 6, and place the spring 42 underan initial compression. Thereafter a continued downward movement of theswaging tool independently of the sleeve and the other elements of thestripper mechanism will cause the taperthe upper collar 38 alsodepresses the latter and ing part 52 of the toolto displace or swagethe; head 44 outwardly so that the same disappears guide sleeve whichenters the enlarged lower part,

of the bore of the lower collar and engages with the downwardly facingshoulder 45, as shown in Pig. 7, thereby locking the lower collar 4|between the lower shoulder 43 and the external head 54 of the guidesleeve and connecting the same, so that the same are firmly united andincapable of being separated by ordinary means.

In order to produce the best effect from the punch it is necessary toguide the same fully to the extreme outer end or cutting edge of its bitand the present invention therefore provides means for accomplishingthis result which are so constructed that a change of punch from onesize to another can be made and still utilize nearly all of the samestripping mechanism with various sizes of punches. In the constructionshown in Figs. 1 and 2 for accomplishing this purpose, a guide button isemployed which has a guide disk 55 bearing with its upper side againstthe lower end of the guide sleeve 31 and its lower collar and adapted torest with its underside on top of the sheet of metal or workpiece whichis to be perforated. At its central part this guide disk is providedwith a guide opening 56 which receives the bit or lower cutting end ofthe punch body and positively guides the same in its movement toward andfrom the workpiece. At its periphery this guide disk is provided with anupwardly projecting annular guide flange 51 which surrounds theperiphery of the lower stripper collar 4| and slides with its peripheralsurface on the bore of the guide opening I5 in the hom-of the punchholder. In this construction the lower stripper collar is spaced fromthe bore of the guide opening IS in the punch holder and the guidebutton 55, 51 therefore performs the whole function of guiding thelowermost end of the punch bit on the holder and maintaining the bit inaccurate alinement with the cutting edge of the slug opening in the die.

When no workpiece is present between the punch guide button and the diethe punching unit which merely floats inv the guide opening II of theholder drops by gravity so that the punch guide button rests on the diebutton. Upon now pushing a workpiece between the die and punch guidebutton, which can be done due to the chamfered, bevelled or cam edge 58on the die and the chamfered, rounded or cam edge I. on the punch guidebutton, the latter together with the punch and stripper elements will belifted by the wedge action of the chamfered edges 5!, 5! when engaged bythe edge of the workpiece. During the subsequent descent of the ram 20the same upon engaging the head and body of the punch will cause thelower cutting or bit end of the punch body to move downwardly in thepunch guide button and into engagement with the workpiece and cut out aslug from the latter so as to form a hole therein, which slug isdischarged through the central opening in the die and the delivery chutein the base of the holder. As the body and head of the punch descend,this head by engaging the top of compresses the stripper spring 42 agreater exa -and' h n oi the ram is moved from of the head and body ofthe punch, the resilience of the spring 42 lifts the h upper collar 3!and also the punch supported thereon and strips the bit of the latterfrom the hole which has been formed in the workpiece.

when it is desired to produce holes or perforations of a diiferent sizein a workpiece it is only necessary to replace the punch and guidebutton by one of the appropriate size and assemble them with the sameguide sleeve 31, upper and lower collars 38, 4| and spring 42, inasmuchas these stripping and guiding elements do not require changingordisassembling but can be used with any size of punch and punch guidebutton. r

By avoiding the necessity of replacing the entire punching unit whenchanging from one size of perforation in the workpiece to another'andinstead only replacing the punch and the punch guide button to meetrequirements and using the same stripper elements in connection withdifferent sizes of punches the cost of the equipment for perforatingholes of diilerent sizes is substantially reduced.

Instead of utilizing the punch guide button as the sole means of guidingthe bit of the punch in the guide opening l5 of the punch and dieholder, as shown in Fig. 1, this guiding effect may be divided betweenthe lower collar of the stripper mechanism and the punch guide button,as shown in Fig, 8. As there shown the lower collar ll of the punchguide sleeve 31 has its upper part of sufllciently large diameter thatthe periphery SI of the same engages with the bore of the guide openingIS in the horn of the punch holder and the upwardly projecting annularflange 62 of the punch guide button also engages the bore of the guideopening I! of the holder horn but surrounds only the reduced lower part63 of the lower stripper collar 80.

In both forms of this improvement shown in Figs. 1 and 8 only the punchand the punch guide button need to be replaced when changing from onesize of perforation in the workpiece to another size and therebyeilecting an economy in doing work of this character.

I claim as my invention:

1. A punching unit for use in connection with a sheet materialperforating apparatus having a holder, a die mounted on the lower partof the holder and a guide opening in the upper part of the holder, saidpunching unit being arranged in said opening and including a punchhaving a vertical body arranged in the center of said opening andterminating at its lower end in a bit and provided at its upper end witha head, a guide sleeve in which said body slides, a lower collar swagedon the lower end of said sleeve, an upper collar slidable on the upperpart of said sleeve and limited in its upward movement thereon andengaged by said head. a spring interposed between said lower and uppercollars, and a lower guide button which is separate from said lowercollar and which has a central guide opening receiving said bit andslidingly engaging its periphery with the bore of said opening in theholder.

2. A punching unit for use in connection with a sheet materialperforating apparatus having a holder, a die mounted on the lower partof the a holder and a guide opening in the upper part of the holder,said punching unit being arranged in said opening and including a punchhaving a vertical body arranged in the center of said opening andterminating at its lower end in a bit and provided at its upper end witha head, a guide sleeve in which said body slides, a lower collar securedto the lower end of said sleeve, an upper collar slidable on the upperpart of said sleeve and limited in its upward movement thereon andengaged by said head, a spring interposed between of the holder, saidpunching unit being arranged in said opening and including a punchhaving a vertical body arranged in the center of said opening andterminating at its lower end in a bit and provided at its upper end witha head, a guide sleeve in which said body'slides, a lower collar securedto the lower end of said sleeve and spaced from the bore of the guideopening in the holder, an upper collar slidable on the upper part ofsaid sleeve and limited in its upward movement thereon, a springinterposed between said collars, and a guide button engaging its upperside with the underside of said lower collar and having a central guideopening which receives said bit and provided with an annular guideflange which projects upwardly between the periphery of said lowercollar and the bore of the guide opening in the holder and slidinglyengaging the latter.

4. A punching unit for use in connection with a sheet materialperforating apparatus including a punch having a cylindrical bodyterminating at one end in a bit, and a head which is separate from thebody and which is swaged on the opposite end ofsaid body.

5. A punching unit for use in connection with a sheet materialperforating apparatus including a punch having a cylindrical bodyterminating at one end in a bit and provided at its opposite end with aplurality of annular grooves,and a head provided with an opening whichreceives the grooved end of said body and secured thereto by displacingmaterial of said head inwardly from the bore of its opening into saidgrooves and thereby interlocking said body and head.

6. A punching unit for use in connection with a sheet materialperforating apparatus including a punch body, a guide sleeve in whichsaid body slides, an upper collar slidable on the upper part of saidsleeve, a lower collar connected with the lower part of said sleeve, anda spring interposed between said collars, said lower collar beingprovided in its bore with adownwardly facing shoulder and said sleevehaving a downwardly facing shoulder engaging the upper side of saidlower collar and having its lower part arranged within said lower collarand expanded into engagement with the downwardly facing shoulder of thelower collar.

GEORGE F. WALES.

